In IEEE 802.11 TGah standard for wireless local area networks (WLANs), the concept of early acknowledgement (ACK) was proposed. A two-bit response frame type indication is added in a signal (SIG) field to indicate whether an immediate response is requested by the sender after a physical layer (PHY) convergence procedure (PLCP) protocol data unit (PPDU). A station (STA), e.g., a wireless communication device, which decodes the SIG field in a received frame correctly, can determine whether to defer channel access based on this indication. The two bits of the SIG field indicate the following type of response frames from the receiver: 00 for an ACK response frame, 01 for a BA response frame, and 10 for a no ACK response frame. The indication 11 can also be used to indicate a data response frame.